Guowei Shu1, Sha Mei1, Qian Zhang1, Ni Xin2, He Chen1

1School of Food and Biological Engineering, Shaanxi University of Science and Technology Xi'an, China
2Department of Research and Development, Xi'an Baiyue Goat Milk Corp., China

Application of the Plackett-Burman design to determine the main factors affecting the anti-oxidative activity of goat's milk casein hydrolyzed by Alcalase and papain

Abstract

Background. Antioxidant peptides can scavenge excessive free radicals produced by the metabolism, main- tain a free radical balance and prevent aging and disease. Therefore, finding natural resources with strong antioxidant activity has become a new focus for research.

Material and methods. Single-factor experiments were used to investigate the effects of various factors (hydrolysis temperature, pH, substrate concentration, enzyme to substrate ratio (E/S), ratio of compound protease (EAlcalase/Epapain) and time on the preparation of antioxidant peptides by compound protease (Alcalase and papain) hydrolysis of goat’s milk casein. Then, a Plackett-Burman design was used to determine the sig- nificant factors for the preparation of antioxidant peptides by hydrolysis of goat’s milk casein with compound protease.

Results. The results of the single-factor experiments indicated that the highest anti-oxidative activity of pep- tides would be obtained at a hydrolysis temperature of 55°C, a pH of 7.5, a substrate concentration of 3.0%, an E/S of 4.0%, a ratio of compound protease of 1/3 and a hydrolysis time of 180 min.

Conclusion. The main factors affecting the activity of anti-oxidative peptides hydrolyzed from goat’s milk casein with compound protease were determined by Plackett-Burman design and the results showed that temperature, E/S ratio and the ratio of compound protease had significant influences on the production of antioxidant peptides. This could provide a basis and reference for further optimization.